Rocket', 'Novelty' and 'Sans Pareil' at the Rainhill Trials (1829) by UnknownNational Railway Museum
The Beginning
In 1829 the Rainhill Trials took place.
The aim?
To find a locomotive to run a new route between Liverpool and Manchester.
The winner?
Rocket!
Illustration of 'Rocket' Locomotive (1859) by Wardale, J. D.National Railway Museum
Rocket was designed by Robert Stephenson and was built in Newcastle. It was one in a line of prototype engines which had been designed for use in coal mining.
However, when the Trials were announced, work was done to ensure that the engine was as fast and efficient as possible. Rocket was at the cutting edge of engineering, but what made Rocket so effective?
Lancashire Witch Locomotive Plan (1828) by Robert Stephenson and C. RichardsonNational Railway Museum
The Design
Earlier engines only had one or two tubes running through the boiler - an example of this style of boiler can be seen in these plans for the earlier Stephenson engine ‘Lancashire Witch’.
Inside Rocket’s boiler, 25 tubes could be found. This is known as a multi-tubular boiler. The extra surface area that came from the series of tubes meant that water could be heated into steam much more efficiently.
The Rastrick Notebook The Rastrick Notebook (1829) by Rastrick, John Urpeth, Mr (author)National Railway Museum
Due to this innovative boiler design, Rocket’s firebox needed to be fitted separately. This firebox was located behind the boiler and was made of copper. A saddle shaped cavity was added around the firebox, which was filled with water.
The separate firebox can be seen in this contemporary sketch made by J.U. Rastrick - a locomotive engineer and one of the judges at the Rainhill Trials.
Other locomotives had their pistons set in a vertical position, as seen here on Puffing Billy - an engine made by William Hedley, Jonathan Forster and Timothy Hackworth c.1813.
Illustration of 'Rocket' Locomotive (1859) by Wardale, J. D.National Railway Museum
Rocket had its pistons set at a 38-degree angle. This meant that when the engine was moving less force was being applied to the tracks and therefore was less likely to cause a breakage. Rocket made use of a connecting rod which directly connected the pistons to the wheels.
Rocket also made effective use of the steam after it had pushed the pistons. This ‘exhausted steam’ was sent through a series of pipes and out of the chimney. This created a draft that would pull air into the firebox.
Working Replica of Rocket (1979) by Locomotion EnterprisesNational Railway Museum
All of these achievements combined to create a state-of-the-art engine which managed to reach a top speed of 30 miles per hour.
Rocket was painted a bright canary yellow, the same colour as the fastest and most reliable horse-drawn coaches of the day. A symbol to any onlooker that it was a design of quality.
Illustration of Rocket with Green Livery (Circa. 1850) by UnknownNational Railway Museum
The Later Years
The pace of railway innovation was so rapid that within months of Rocket’s triumph, it was already considered outdated. By 1836, Rocket was no longer in service on the main line and had been reassigned as a colliery engine.
This drawing was made when Rocket was being sold to a colliery and shows us some of the alterations that had been made.
Rocket had lost its yellow livery, and is green instead.
The piston is now set at an 8-degree angle. This provided a much smoother ride at high speeds.
A steam dome was added. This provided a space for a reservoir of steam and allowed for the water level in the boiler to be raised.
Rocket’s distinctive petaled chimney had been replaced. This chimney was fitted with a screen to stop sparks being released out of the top.
This smokebox was fitted to the front of the engine. This allowed air to circulate through the engine more effectively. This smokebox was also fitted with a door at the front, so it could be more easily cleaned.
After a period of colliery service, Rocket was eventually retired. At some point following its withdrawal, the copper firebox was removed, likely due to the value of the material. In 1851, Rocket was returned to Robert Stephenson & Co., where it was left to rust.
Rocket Locomotive, Patent Office Museum (1829) by Stephenson, Robert and Robert Stephenson & Co.National Railway Museum
The End of the Line
In 1857, Rocket was displayed at the Patent Office Museum, and later the South Kensington Museum (which eventually became the Science Museum). Here we can see Rocket outside the South Kensington Museum in 1876 and it has changed again.
A replacement firebox was added.
A copy of Rocket’s original chimney was fitted.
Rocket Locomotive, 1876 (1829) by Stephenson, Robert and Robert Stephenson & Co.National Railway Museum
Even less than 50 years after it was built, it was clear that Rocket was an important artefact of the early railways and was worth preserving. But it was uncertain whether the engine should be left in its final condition, or whether it should be restored to its original design.
Rocket Locomotive (1829) by Stephenson, Robert and Robert Stephenson & Co.National Railway Museum
150 years later, Rocket is still on display. But it has once again changed.
The false firebox has been removed.
The chimney has been changed to try and reflect how Rocket looked at the end of its working life.
The metal has been left unpainted, neither yellow nor green.
The Rocket that exists today is a result of decades of updates, alterations and decay. It is in a strange state of limbo, not fully reflecting what it looked like during any part of its working life.
However, it is a testament to the rapid changes of early railway engineering, and more than a century-long desire to preserve these innovations for generations to come.
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